Ancestral property right for inheritance and sell

Hi All Respected Lawyers on Board,

                   I am a resident of Bihar. I am the eldest of four Brothers and all my other brothers are major. My father is in hold of our ancestral property. Actually my father inherited this property from my father's father who in turn have inherited from his father as illustrated by this flow chart A (original purchaser of property) --> B --> C (my father) --> D (we four brothers). 

                 Ours is stll a joint family and the division of property has not been done amongs our father's brothers. Recently I came to know that my father has sold almost 109200 Sq feet of land without ours knowledge and without even the knowledge of our uncles. He has enjoyed all the money by selling the land and still wanted to sell the  remaining.

                 I just wanted to know that whether he has right to sell that ancestral land without the approval of my uncles and without ours approval. The person who has bought the land from my father has how much legal right to hold it. What is our right in that land.

            We brothers wanted to get back our share of land which he has illegally sold out. Please help me by suitable legal advice for recovery of my lost land and also help me by guiding the provisions to stop my father from selling any ancestral land in future.

Thanks in advance

Dhirendra